A wide variety of absorbent catamenial tampons have long been known in the art. Most currently commercially available tampons are made from a tampon pledget which has been compressed into a substantially cylindrical form. Tampon pledgets of a variety of types and constructions have been described in the art. Prior to compression, the pledget may be rolled, spirally wound, folded, or assembled as a rectangular pad of absorbent material. Tampons made from a generally rectangular pledget of absorbent material have been popular and successful in the market.
The absorbent catamenial tampons now in use typically comprise absorbent members which are compressed to a generally cylindrical form about three-eighths to one-half inch (about 1.0 cm to 1.3 cm) in diameter and from about 2 cm to 7 cm in length. In order to provide the desired total absorbency, these absorbent members are usually formed from batts larger in size than the vaginal orifice, which are then compressed to the size (with a corresponding increase in rigidity) indicated above in order to facilitate insertion. As fluid is absorbed, these compressed tampons are expected to re-expand toward their original pre-compressed size, and to eventually become large enough to effectively cover the vaginal cavity against fluid leakage or bypass. While it has been found that these compressed tampons perform their intended function tolerably well, even the best of them do not always re-expand sufficiently, or fast enough, to provide good coverage against leakage.
The prior art has long recognized various mechanisms by which tampons might fail to deliver superior performance. One such mechanism is often referred to in the art as "bypass" failure. Bypass failure occurs when the menses travels along the length of the vagina without contacting the tampon, i.e. the tampon fails to intercept the flowing menses.
A variety of approaches have been attempted in the prior art to address bypass and other forms of tampon failure. One series of attempts has included the use of a conventional cylindrical, compressed tampon in combination with a secondary or "backup" structure. One example of such an attempt is described in U.S. Pat. No. 3,101,714 issued to Penska. The Penska device consists of a typical elongated cylindrical body of absorbent material with an absorbent withdrawal cord. A plug or pad of absorbent material is slidably mounted on the cord. During normal flow times, the plug member may be removed from the cord. In times of heavier flow, the plug may be slid upward on the cord, after insertion, to be held in place by the sphincter muscles of the vagina. While appearing to address some of the problems associated with bypass flow, the Penska, device suffers from some significant drawbacks. For example, the withdrawal cord of the device is absorbent which has the tendency to retain deposited fluid along the entire length of the cord and, consequently, outward of the orifice of the vagina. Additionally, the slidable plug of the absorbent device resides at least partially externally to the vagina and is held in place by the sphincter muscles thereof. Because the plug of the Penska device cannot be slid into place until after insertion of the tampon portion, a completely internal disposition (i.e. intervaginal placement) of the plug cannot be achieved.
Another prior art approach is described in U.S. Pat. No. 2,123,750 issued to Schulz. The Schulz device consists of an essentially conventional cylindrically shaped absorbent portion with a withdrawal end "flare" of material attached thereto. The withdrawal end flare, however, is comprised of a non-absorbent material and extends outwardly in the radial direction beyond the outer diameter of the cylindrical absorbent portion. This reduces both the comfort associated with the Schulz device, as well as its effectiveness, since the additional material is non-absorbent and, therefore, of marginal usefulness.
Yet another approach is described in U.S. Pat. No. 3,307,506 also issued to Penska. This device generally consists of a tampon attached by the withdrawal cord thereof to a sanitary napkin. This device also suffers from the disadvantage that only external placement of the secondary absorbent member is possible.
While many of the above-described devices and other tampons currently available have been successful and have gained acceptance in the marketplace, the search for an improved absorbent tampon has continued. Each of the above-described devices suffers from certain drawbacks, as noted, which are addressed by the development of the present invention.
During development of the present invention, it has been found that it is desirable to provide a catamenial tampon which may be constructed of materials such as rayon and cotton which have long been used in the art for absorption of menstrual and other vaginal discharges. Such materials are accepted as safe and effective for such in-vivo application, are readily available, and are sufficiently inexpensive for disposable product application. It is also desirable to design a tampon which may be inserted digitally or through the use of conventional "tube and plunger" applicators since such applicators are well accepted by consumers and are easy and inexpensive to manufacture. It is also desired to provide a tampon which is comfortable and which does not depart from currently approved regulatory absorbency ranges. A superior design will achieve all of these goals, while also minimizing bypass leakage associated with the tampon. This is accomplished through the unique design of the present invention which resides in an optimal location within the vaginal vault and which is provided with a superior mechanism for bypass prevention.